Refractive index and absorbance of graphite powder
I have already said, the color change, that change the material inside, you have not had the measured absorbance of the substance determination in you have set the wavelength of the sum of the original material, but a new generation of absorption material and the residual absorbance. The original substance must have been reduced, and its contribution to absorbance is correspondingly reduced, but the newly formed material may have a stronger absorption at this wavelength, so the overall result is an increase in absorbance. If you want to use absorbance analysis, you must select a suitable wavelength so that only the material you wish to measure at this wavelength is absorbed without interference from other substances.
When the matter to be measured is different, or the wavelength chosen is different, the molar absorption coefficient will be different, so that it can not meet the quantitative relationship of Bill's law.
Color changes indicate that the absorption of light inside the material has changed, it can not be compared by the size of the relative content of absorbance. By absorbance, the content must be of the same substance and comparable at the same wavelength.
